Using a broad spatula, mark candy surface in 1/2-inch squares. Do not break film on surface. (If candy doesn't hold its shape, it isn't cool enough to mark. Let stand a few more minutes.)

Retrace previous lines, pressing spatula deeper each time, but not breaking the surface until the spatula can be pressed to the bottom along all lines. (If candy hardens before the pieces are cut, put it in a warm oven for a few minutes.)

Cool completely. Use foil to lift the candy out of the pan; break candy into squares. Roll candy pieces in powdered sugar; shake off excess. Makes 1 pound candy.